Memory Module Assembly and Heat Sink thereof

ABSTRACT

A memory module assembly includes a plurality of memory modules and a heat sink assembly. Each of the memory modules includes at least one heat source. The heat sink assembly includes a heat dissipating plate and a plurality of heat transfer mediums. Each of the heat transfer mediums includes a base attached to the heat dissipating plate, and at least one resilient sheet extending from an end of the base. The base and the resilient sheet define an included angle which is non-right angle so that the resilient sheet can snugly clip to the respective heat source.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of co-pending application Ser. No. 11/767,493,filed on Jun. 23, 2007.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a memory module assembly and a heatsink assembly configured to be fitted to the memory module assembly, andin particular to a heat sink assembly for radiating heat generated froma fully buffered dual in-line memory module (FBDIMM), a printed circuitboard (PCB) of the FBDIMM on which the advanced memory buffer (AMB)package is mounted.

2. Related Prior Art

A memory module may be classified into a single in-line memory module(SIMM) and a dual in-line memory module (DIMM). The SIMM includes a rowof memory chips mounted on only one side of the PCB, and the DIMM hastwo rows of the memory chips mounted on both sides of the PCBrespectively.

In order to improve transmission efficiency, a fully buffered DIMM(FBDIMM) has been provided. FBDIMM has a hub, such as an advanced memorybuffer (AMB) logic chip that is mounted on the center of the memorymodule. The AMB chip receives packet signals including a memory commandand/or data from an external host (e.g., a memory controller), andprovides the received data to respective memory chips. In addition, theAMB chip packetizes data outputted from the memory chips, and providesthe packets to the memory controller. In the FBDIMM, signals fromexternal sources are transmitted to the respective memory chips via theAMB chip. Accordingly, all signal lines on which the signals aretransmitted are coupled to the AMB chip. Consequently, a large load isconcentrated on the AMB chip and high heat may be generated in the AMBchip. High heat reduces the life span of the AMB chip and lowers theoperational reliability of peripheral circuits of the AMB chip. Hence,it is advantageous to quickly dissipate away the heat from the AMB chip.

As shown in FIGS. 11 and 12, Taiwan Patent No. 1273688 discloses amemory module integrated mechanism 100 mounted on a motherboard 200,which comprises a plurality of FBDIMMs 110 and a heat sink 120. Each ofthe FBDIMMs 110 includes a PCB 111, a row of memory chips 112 mounted onthe PCB 111, an AMB chip 113 attached to one of the memory chips 112,and a heat sink plate 114. The heat sink plate 114 is attached to theAMB chip 113 and is parallel to the PCB 111 for radiating heat generatedfrom the AMB chip 113. Furthermore, the heat sink 120 is disposed abovethe FBDIMMs 110 and contacts with each one of the heat sink plates 114of the FBDIMMs 110. The heat sink 120 comprises a heat dissipating plate121 and a plurality of clipping members 122 extending from the heatdissipating plate 121. The heat dissipating plate 121 is perpendicularwith each one of the PCBs 111 of the FBDIMMs 110. Each of the clippingmembers 122 extends toward the respective heat sink plate 114 andincludes two parallel clipping sheets 122 a as depicted in FIG. 12. Atop portion of each of the heat sink plates 114 is sandwiched in betweenthe two respective clipping sheets 122 a. However, there is notdisclosed how the clipping members 122 and the heat dissipating plate121 are connected in the specification. Generally, the connection may befulfilled by welding or the like, but requiring much time and work. Inaddition, the two parallel clipping sheets 122 a can only contact thetop portion of the heat sink plate 114, which means only little area ofthe heat sink plate 114 is used for heat transferring to the heatdissipating plate 121. Hence, the heat dissipating efficiency islimited.

SUMMARY OF INVENTION

The primary object of this invention is therefore to provide an improvedheat sink assembly of a memory modules assembly, which is easy to beassembled and provides increased heat dissipating efficiency.

According to the present invention, a memory module assembly and a heatsink assembly applying for the memory module assembly are disclosed. Thememory module assembly comprises a plurality of memory modules and theheat sink assembly. Each of the memory modules includes at least oneheat source, such as an AMB chip. The heat sink assembly comprises aheat dissipating plate and a plurality of heat transfer mediums. Each ofthe heat transfer mediums includes a base attached with the heatdissipating plate, and at least one resilient sheet extending from anend of the base. The base and the resilient sheet define an includedangle which is non-right angle so that the resilient sheet can snuglyclip to the respective heat source by resilience.

Preferably, the heat dissipating plate defines at least one slittherein. The resilient sheet is inserted into the slit to clip to theheat source. The heat transfer medium further includes a fasteningportion disposed on the resilient sheet so that the base can be firmlyattached to the heat dissipating plate.

Further benefits and advantages of the present invention will becomeclear as the description proceeds.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be elucidated with reference to the followingdescription and accompanying drawings where:

FIG. 1 is an exploded view of a memory module assembly of the preferredembodiment being mounted on a motherboard according to the presentinvention;

FIG. 2 is a perspective view of FIG. 1;

FIG. 3 shows a load punching on a base of a heat transfer medium so asto bend a heat dissipating plate;

FIG. 4 shows a view of FIG. 3 after punching;

FIGS. 5 and 6 illustrate a first example of the heat transfer mediumbeing fit into memory modules;

FIGS. 7 and 8 illustrate a second example of the heat transfer mediumbeing fit into the memory modules;

FIG. 9 illustrate s a third example of the heat transfer medium beingfit into the memory modules;

FIG. 10 illustrates a fourth example of the heat transfer medium beingfit into the memory modules; and

FIGS. 11 and 12 are views of a prior art.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

With reference to FIGS. 1 to 10, description will be given of a memorymodule assembly including a heat sink assembly 4 according to thepreferred embodiment of this invention.

FIG. 1 shows that the memory module assembly comprises a plurality ofmemory modules 3 mounted on a motherboard 2, and the heat sink assembly4.

Each of the memory modules 3, such as an FBDIMM, comprises a PCB 31, aplurality of memory chips 33, two hub chips 34 (eg. an AMB chip), andtwo heat sink plates 32. The memory chips 33 are mounted on both sidesof the PCB 31. Each side of the PCB 31 includes one hub chip 34 mountedon one of the memory chips 33. The hub chips 34 are configured toconnect memory chips 33 via a respective memory chip interface. Asmentioned above, a large load is concentrated on each of the hub chips34, namely the AMB chips, and high heat may be generated in the hubchips 34, namely heat sources. The heat sink plates 32 are attached tothe hub chips 34 respectively for radiating heat generated from the hubchips 34.

It should be noted that the heat source of this embodiment is the AMBchips while in other instance, a heat source may be just a memory chipwhen a traditional SIMM or DIMM is used, where there is no hub chipthereon. In that kind of case, the heat sink plate can be directlyattached to the memory chip.

In this preferred embodiment, the heat sink assembly 4 comprises a heatdissipating plate 40, a plurality of heat transfer mediums 41, and twofans 43.

The heat dissipating plate 40 defines a plurality of slits 401corresponding to the heat transfer mediums 41, and two through holes 402corresponding to the two fans 43. Each of the heat transfer mediums 41includes a base 410, two resilient connecting sheets 411 and fourfastening portions 412. The two resilient sheets 411, such as coppersheets, extend from opposite ends of the base 410. Referring to FIG. 2,the two resilient sheets 411 are inserted into a pair of the slits 401,and thereby a bottom of the base 410 can be right attached to a top ofthe heat dissipating plate 40. Referring back to FIG. 1, two of the fourfastening portions 412 extend outward from an upper portion of therespective resilient sheet 411, namely outwardly biased, for holding toa bottom of the heat dissipating plate 40. Because of being outwardlybiased in the beginning, the fastening portions 412 can be compressed tobe aligned with the resilient sheets 411, and can return to openoutwardly again once released. Thus while the resilient sheets 411 arebeing inserted into the slits 401, the four fastening portions 412 arecompressed as a result of the small slits 401. For this, a load 5 can beused to punch the base 410 of the heat transfer mediums 41, as shown inFIG. 3, so that the heat dissipating plate 40 can be bent upward a bitand the slits 401 be enlarged to a degree that the fastening portions412 can bounce out from the slits 401 to abut against the bottom of theheat dissipating plate 40. After the load 5 is lifted up, as shown inFIG. 4, the heat dissipating plate 40 is released and the fasteningportions 412 keep upholding the heat dissipating plate 40. In such amanner, the base 410 can be firmly attached to the heat dissipatingplate 40.

As shown in FIG. 5, before the heat sink assembly 4 is attached to thememory modules 3, the two resilient sheets 411 of each of the heattransfer mediums 41 are inwardly biased in the beginning. When the heatsink assembly 4 and the memory modules 3 are engaged as shown in FIG. 6,the two resilient sheets 411 are placed around one of the memory modules3 and snugly attached to the two opposite heat sink plates 32 of thememory module 3 respectively. In such a manner, the heat sink assembly 4can be perfectly fit in between the memory modules 3

In another example, the two resilient sheets 411 of each of the heattransfer mediums 41 may be outwardly biased in the beginning, as shownin FIG. 7, so that the two resilient sheets 411 can be placed in betweenadjacent two of the memory modules 3 and snugly clip to thecorresponding opposing heat sink plates 32 of the adjacent two memorymodules 3, as shown in FIG. 8.

In yet another example, as shown in FIG. 9, each of the heat transfermediums 41 may has only one resilient sheet 411 with one fasteningportion 412 thereon. The resilient sheet 411 and the base 410, asindicated by phantom lines, define an obtuse angle, larger than 90degrees, so that the resilient sheet 411 can be placed in acorresponding position so as to snugly clip to the right heat sink plate32 of the respective memory module 3.

Similarly, as shown in FIG. 10, the resilient sheet 411 and the base 410define an acute angle, smaller than 90 degrees, so that the resilientsheet 411 can be placed in another corresponding position so as tosnugly clip to the left heat sink plate 32 of the respective memorymodule 3.

Accordingly, as long as the resilient sheet 411 and the base 410 definean included angle which is non-right angle, the resilient sheet 411 cansnugly clip to the right or left heat sink plate 32 of the respectivememory module 3.

Referring back to FIG. 2, the fans 43 are mounted on the heatdissipating plate 40 facing the through holes 402. In this manner,airflows generated by the fans 43 can be guided toward the memorymodules 3 via the through holes 402 to enhance cooling of the memorymodules 3.

Numerous characteristics and advantages of the invention have been setforth in the foregoing description. The disclosure, however, isillustrative only, and changes may be made in detail within theprinciple of the invention, to the full extent indicated by the broadgeneral meaning of the terms in which the appended claims are expressed.

1. A heat sink assembly comprising: a heat dissipating plate having atop surface, a bottom surface and a first slit extending through theheat dissipating plate from the top to bottom surfaces; and a heattransfer medium including a base secured on the top surface of the heatdissipating plate and a first connecting sheet extending from an end ofthe base and through the first slit for snugly joining to a side of afirst heat source.
 2. The heat sink assembly of claim 1 wherein the heatdissipating plate further has a second slit extending through the heatdissipating plate from the top to bottom surfaces; and the heat transfermedium further has a second connecting sheet extending from the oppositeend of the base and through the second slit for snugly joining to theopposite side of the first heat source.
 3. The heat sink assembly ofclaim 2 wherein the first and second connecting sheets are bothresilient and each is inclined with respect to the base.
 4. The heatsink assembly of claim 1 wherein the heat dissipating plate further hasa second slit extending through the heat dissipating plate from the topto bottom surfaces; and the heat transfer medium further has a secondconnecting sheet extending from the opposite end of the base and throughthe second slit for snugly joining to a side of a second heat source. 5.The heat sink assembly of claim 4 wherein the first and secondconnecting sheets are both resilient and each is inclined with respectto the base.
 6. The heat sink assembly of claim 1 wherein the heattransfer medium further includes a fastening portion extending from aside of the first connecting sheet, and the fastening portion upwardlyabuts against the bottom surface of the heat dissipating plate in orderto firmly attach the base to the top surface of the heat dissipatingplate.
 7. The heat sink assembly of claim 1 further comprising a fan,wherein the heat dissipating plate further has a through hole where thefan is mounted.
 8. A heat sink assembly comprising: a heat dissipatingplate having a top surface and a bottom surface; and a heat transfermedium including two resilient sheets extending from the bottom surfaceof the heat dissipating plate; the two resilient sheets being outwardlybiased in order to be snugly sandwiched in between two adjacent heatsources.
 9. The heat sink assembly of claim 8 further comprising a fan,wherein the heat dissipating plate further has a through hole where thefan is mounted.
 10. A heat sink assembly comprising: a heat dissipatingplate having a top surface and a bottom surface; and a heat transfermedium including two resilient sheets extending from the bottom surfaceof the heat dissipating plate; the two resilient sheets being inwardlybiased in order to snugly clip to opposite sides of a heat source. 11.The heat sink assembly of claim 10 further comprising a fan, wherein theheat dissipating plate further has a through hole where the fan ismounted.